The present invention relates to a silver halide photographic photosensitive material which has a printability from color negative films and furthermore, which is usable as a variable contrast paper for at least black and white negative films using tone varying filters adjusted by selecting wavelengths which transmit therethrough and to a printing process using the photosensitive material. The present invention further relates to a photographic photosensitive material usable as a variable contrast paper not only for black and white negative films, but also for color negative films using tone varying filters adjusted by selecting wavelengths which transmit therethrough.
In general, as black and white printing papers, those which differ in grade of contrast from No.1 to No.5 depending on the contrast of the black and white negative films to be contact-printed or enlargement-printed are separately assorted and marketed. However, in order to obtain optimum prints depending on various negatives, users must manufacture printing papers of many kinds of grades in contrast, and if frequency in use of them is small, the quality of them may change in storage. For solving this problem, the variable contrast printing paper is known from which prints differing in contrast can be obtained with one printing paper by adjusting the exposure wavelengths by selecting optical filters differing in wavelength which they can transmit (tone varying filters).
Recently, there are many chances to take color photographs and in many cases, we use only one camera loaded with a color film. In this case, the demand increases that not only color prints, but also black and white prints can be obtained from the photographed color films. However, when printed on the conventional No.1-No.5 contrast printing papers or variable contrast printing papers, no prints having satisfactory quality in contrast have been able to be obtained. Therefore, black and white printing papers have been desired on which black and white printing of excellent quality can be performed from color negative films with one photosensitive material and furthermore, by which a high finishing quality from black and white negative can be obtained.
For printing of color negatives on black and white printing papers, so-called panchromatic black and white printing papers having sensitivity to blue, green and red are generally used. This is because, being different from black and white negatives, the color negatives comprise three dye images of Y, M and C and the printing papers must have sensitive portions for the whole wavelength regions of visible light in order to obtain the higher fidelity tone reproduction and excellent graininess and sharpness. Furthermore, when handleability under the lighter safelight is required, orthochromatic photosensitive materials are sometimes used, but for lack of red sensitivity, the materials are inferior in color reproducibility and graininess.
Moreover, as for the tone reproduction, in the case of color films like the black and white films, negatives of from low contrast to high contrast characteristics are produced depending on the conditions at the time of photographing and besides, the tone differs depending on the kind of the color films even if correct exposure is conducted. Therefore, in order to obtain finally satisfactory positive prints, it is not enough for color films only to have panchromatic color sensitivity and it is necessary to assort printing papers differing in contrast from low contrast to high contrast. Thus, the manufacturers sell panchromatic black and white printing papers shown by tone numbers.
The manner of use of panchromatic black and white printing papers can be roughly classified into manual printing by an enlarger in a dark room and printing under roomlight by a printer united with a processor. In the case of the manual printing, for obtaining good prints, printing papers of optimum tone number are selected and used according to the tone of the negatives among a plurality of printing papers differing in contrast. Accordingly, there are problems that the number of expired printing papers increases due to increase in stock or decrease in frequency in use. Furthermore, in order to obtain satisfactory prints when printing is carried out by a printer united with a processor, the printing paper must be changed depending on the tone of the color negative, but since this causes reduction of working efficiency, actually the printing is carried out with one printing paper and at present, no measure is taken for adaptation to the tone of the negative. As a measure, there is a process of printing by auxiliary exposure, but from the point of characteristics, only the tone of tip of toe of characteristic curve is controlled and with increase of the auxiliary exposure, the characteristic curve is extended and curved in the tip of toe and this does not mean ideal characteristics and besides, this causes increase of fog and fluctuation of sensitivity. Thus, the conventional panchromatic black and white printing papers are not necessarily satisfactory for users.